ELI5- how do rice cookers know how long to cook the rice for no matter the different quantities

Question

ELI5- how do rice cookers know how long to cook the rice for no matter the different quantities

In: Other

Answer 1

If there’s still liquid water in the pot, the max temperature is 212F/100C. When it runs out of water, then the temperature can climb past 212F. Put in a switch (bimetallic strip) to turn off the machine when it hits 215-220ish (or whatever the margin of error is) and you have an extremely simple, purely mechanical system that will run until the water boils off then turn off when it starts to heat beyond boiling.

Same principle for the simplest Coffee Machines or Kettles that go until they run out of water.